Phil Clauer is an extension poultry specialist at Penn State University. He says scaly leg mites can be found any time of the year, but are most common in the summer and fall. Mites crawl up legs and bury themselves under the scales.

"The scales get very coarse, and they almost become risen, and sometimes they get infected to where the foot leg just looks real coarse and rough, and just not right," he says. "It doesn't look nice and smooth like it should. And if you get a bad infestation, the bird will go lame from that. It'll get infected and it'll go down."

The leg can thicken to look twice its size, and appear very knobby. Never try to remove affected scales. This is painful for your chicken. However, the mite problem will only get worse over time if not treated.

Clauer says the only treatment is to suffocate the mites.

"What you have to do is find some kind of a petroleum-based product that you can smear on the legs above and around the scales so that there's no way that the mite can breathe," says Clauer. "The mite will die if you treat it a couple times, and then within a few weeks those old, rough, coarse scales will typically shed. Because that's what happens with old scales, they shed off just like dried skin, and then they'll look nice and new again underneath."

Isolate any chickens that are infected, because leg mites spread quickly. It's also important to thoroughly clean out the chicken coop and disinfect its accessories.

Prevention is easier than treatment. Chickens with feathered feet are prone to scaly leg mites, so they should be checked on a regular basis. If you add new adult birds to the flock, be sure to inspect them first.